The answer depends if we're taking a long haul flight with long or short layovers in certain provinces or countries.
My last experience flying home took me:
from Toronto to Vancouver is 4 to 5 hrs, and
from Vancouver to another area in Asia for refuelling is 11 to 12 hrs,
another 1.5 to 2 hrs to Manila.
Just imagine the excitement of going around the world in 18 hrs, give or take. We will have lots of activities on air for sure!